Safety apparatus for remote control of valves

ABSTRACT

Safety apparatus for the remote control of valves, particularly valves controlling sluices or water gates disposed at the head of an underwater oil well, including means for effecting the opening of the valve in response to either a hydraulic or electrical signal emanating either from a central control location monitoring a plurality of valves or from a location associated with only a single valve, and maintaining the control system in an energized state until a signal is generated, either by a device monitoring certain flow parameters or by a manual control, to permit the system to be deenergized, thus causing the valve to return to a closed position.

United States Patent n 13,5s2,03s

[72] Inventors Jacques Harboun Jouars Ponchartrain; Emile bevallois, Martigues, both of, France [21] Appl No. 839,536 [22] Filed July 7, 1969 [45] Patented June 1, 1971 [73] Assignee lnstitut Francais Du Petrole, Des

Carburants Et Lubrifiants Rueil Malrnaison (Hauts de Seine), France [54] SAFETY APPARATUS FOR REMOTE CONTROL OF VALVES 10 Claims, 4 Drawing Figs.

52 u.s.c| .Q 251/71, 25 1/7 3 [51] Int. Cl Fl6lt 31/44 [50] FieldofSearch 251/71,73

[56] References Cited UNITED STATES PATENTS 3,164,359 1/1965 Dyer et a1. 251/73X 3,430,916 3/1969 Raymond 251/71 FOREIGN PATENTS 427,695 4/1926 Germany 251/71 Primary Examinerl-lenry T. Klinksiek Att0rneyCraig, Antonelli, Stewart & Hill ABSTRACT: Safety apparatus for the remote control of valves, particularly valves controlling sluices or water gates disposed at the head of an underwater oil well, including means for effecting the opening of the valve in response to either a hydraulic or electrical signal emanating either from a central control location monitoring a plurality of valves or from a location associated with only a single valve, and maintaining the control system in an energized state until a signal is generated, either by a device monitoring certain flow parameters or by a manual control, to permit the system to be deenergized, thus causing the valve to return to a closed position.

PATENTED JUN 1 I97! 3; 582,038

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ATTORNEYS PATENIEDJUN Hen 3582.038

sum 2 or 2 an INVENTORS rn euss HARBONN d EMILE LEVALLOIS ATTORNEYS SAFETY APPARATUS FOR REMOTE CONTROL OF VALVES BACKGROUND OF THE INVENTION The presentinvention pertains to a safety device for the remote control of valves.

The apparatus contemplated by the present invention may, for example, be. adapted to each of the valves or gates disposed at the headsof an underwater oil well and provide for selectively controlling the opening and closing of each of these gates from a central, remotely controlled station as well as from a location situated above the wellhead, such as an installation immersed at a slight depth or situated at the surface of the water, substantially perpendicular relative to the well.

In accordance with the present invention, the apparatus may incorporate either hydraulic or electrical devices for generating the signals controlling the operation of the valve.

One particularly significant feature-of the apparatus contemplated by the present invention includes the provision of a safety mechanism including. an elastic means for returning the valve to its closed position after the system has been placed and maintained in an energized state by the remotely controlled opening of the gate and in the absence of a subsequent signal to close same. The closing of the valve maybe effected either by means of a manual remote control or by means of a signal generated by meansof measuring instruments disposed at the wellhead and automatically monitoring certain flow parameters, such as the rate of flow and the pressure of the fluiddischarged.

Accordingly, it is an objective of the present invention to provide safety apparatus for remotely controlling the selective opening and closing of valves either from a remotely controlled central station or from a location associated only with an individual valve.

Further, it is an objective of the present invention to provide apparatus of the type described above which can accomplish theidesired functions either by means of hydraulic or electrical devices.

It is an additionalobjective of the present invention to provide apparatus of the type described above which incorporates significant safety features, particularly in that when the valves are in an open position, they are maintained in a constant state of stress or energization such that they will automatically be returned to a closed position in response to a signal generated upon reaching some predetermined value of a specific flow parameter or by a remotely operated manual control.

Finally, it is an objective of the present invention to provide apparatus of the type: described above including as elastic device for restoring the valves to a closed position, wherein the elastic device is associated with the valve such that, when thevalves are in an open position, the elastic device-exerts a torque upon the rotary valve, the value of which torque remains substantially constant until the complete closure of the-valve has been accomplished or at least to the extent that the value of the torque remains sufficient to ensure the complete closure of the valve.

SUMMARY OF THE INVENTION The aforementioned objectives are accomplished, in accordance with the present invention, by the provision of a key member directly controlling rotation of the valve between its open and closed positions, which key member includes an operating element having an axis of articulation, an elastic device adapted to exert upon the operating element a force tendingto return the key member toward a position wherein the valve is closed, the control system including at least one camsubjected to the action of the elastic device, the profile of which is applied at a point of the operating member effective to transmit or impart thereto the necessary returning force, and a'driving assembly, remotely controlled for actuating and maintaining the cam in a position corresponding to an open valve position. while simultaneouslymaintaining the elastic device in a state of stress. The profile of the cam is designed such that the distance between the axis of articulation of the operating member and the force exerted by the elastic device thereupon substantially varies in a manner inversely proportional to the force exerted by the elastic device in the course of its expansion.

BRIEF DESCRIPTION OF THE DRAWINGS The structure and operation of the apparatus contemplated by the present invention will become more readily apparent from a consideration of the detailed description hereinbelow, when considered in conjunction with the accompanying drawings, wherein:

FIG. 1 schematically represents a valve of the rotary type which may advantageously be controlled by the apparatus constructed in accordance with the present invention;

FIG. 2 schematically represents a first embodiment of apparatus constructed in accordance with the present invention, wherein the control is effected hydraulically;

FIG. 3 schematically represents an alternative embodiment of the apparatus constructed'in accordance with the present invention, wherein the control is effected electrically; and

FIG. 4 represents an alternative embodiment of the apparatus contemplated by the present invention, wherein the control is effected electrically.

DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1. schematically illustrates a valve which may be provided at the head of an oil well. This valve, which is of the rotary type, includes a control key 3 integral with a spherical portion 33 adapted to turn, by rotation of the key 3 about its axis, within a spherical housing or hollow portion 34. A passage 35 is disposed within the spherical portion 33 of the valve. When the valve is in an open position, the fluid flowing therethrough follows the path indicated by the arrows.

In the open position of the valve, a stop or detent (not shown) provides for the precise positioning of the spherical portion 33 within the housing 34 so that the passage 35 is in proper alignment withthe inlet and outlet conduits of the valve. This precise alignment is particularly necessary in order to permit the passage of tools in the discharge conduit of the valve.

One embodiment of the control apparatus contemplated by the present invention, including a hydraulic drive, is represented in FIG. ,2. In that Figure, reference numeral 1 represents a fluidtight casing or box in which the elements of the device are disposed within a hydraulic medium.

The fluidtight nature of the casing, which is achieved in a conventional manner by employing fluidtight joints (not shown) will be better assured if the pressure differential existing between the inside and the outside of the casing is minimized. Additionally, the minimizing of the pressure differential serves to prolong the service life of the fluid tight joints.

When the device is immersed, the pressure outside of the casing 1 is equal to the hydrostatic pressure prevailing at the depth of the wellhead, whereas the pressure at the inside of the casing 1 is that which corresponds to the height of the hydraulic medium filling within the casing. Thus, the pressure differential can be minimized since it is proportional to the density differential between sea water and the hydraulic medium employed. Preferably, the hydraulic medium is an oil emulsion in water containing, for example, 15 percent oil. The use of such a hydraulic medium serves to minimize the pressure differential.

In accordance with a preferred embodiment of the present invention, illustrated in FIG. 2, a deformable diaphragm 2 further serves to balance the internal and external pressures. Alternatively, however, it is also feasible to construct the fluidtight casing 1 of sufficient strength as to withstand the prevailing pressure differential between the inside and outside thereof.

As seen in FIG. 2, the operating member of the key 3 of the valve to be controlled consists of a lever 4 which is articulated at 32 about an axis fixed with respect to the casing l. The lever 4 is equipped with a toothed sector 5 which is in operative engagement with another toothed sector 6 wedged on the key 3 of the valve so as to effect the opening (by rotation in the direction of the arrow 0 of the toothed sector 6) or the closing (by rotation in the direction of the arrow F of the toothed sector 6) of the valve.

The lever 4 is in operative engagement with a cam 8 which is integral with one of the extremities of a compression spring 7. The cam 8 is further connected, by means of a rod 19, with a piston 9 which is adapted to move, with only minimal play, within the cylinder 31. The cylinder 31 is supplied with hydraulic medium under pressure for purposes of effecting selective control of the valve. The hydraulic fluid under pressure may be supplied to the cylinder 31 through either one or several remotely controlled hydraulic ducts or lines, such as the duct 10 and 13.

The duct 10 will be connected, for example, with a central, remote control station where the oil well is one of a group of under water oil wells and the duct 13 may be connected with a surface buoy disposed substantially perpendicular to the individual well so as to serve as an auxiliary or emergency control line operably by service personnel who approach in a small boat for purposes of closing the valve in the event that the desired control can not be effected by means of the line 10.

The ducts 10 and 13 are in communication with a first chamber 31a of the cylinder 31 by means of a distributor 11 comprising a supply conduit 36 communicating with the compartment 31a of the cylinder 31 through a calibrated flap valve 14 which seals conduit 36 in the absence of a sufficient supply or feeding pressure in either one or the other of the ducts 10 and 13.

The distributor 11 comprises a feeder conduit 18 and a junction conduit 37 providing communication between supply conduit 36 and a second chamber 31b of the cylinder 31 at a point of supply conduit 36 downstream of the flap valve 14, with respect to the direction of flow of fluid under pressure being conveyed towards the cylinder 31.

The feeder conduit 18 comprises a calibrated flap valve 15 which serves to close off this conduit in the presence of a hydraulic medium supply pressure of sufficient magnitude in either one or the other of the ducts 10 and 13. In the illustrated embodiment, the signal for closing off the feeder conduit 18 by means of the flap valve 15 is obtained by means of a piston 16 which is'adapted to move within a cylinder 38, one chamber of which communicates with the supply conduit 36.

The remote control ducts 10 and 13 terminate in the same chamber 39 into which the supply conduit 36 opens. The chamber 39 encloses a ball 12 which, when the pressure of the hydraulic medium supply in one of the conduits 10 and 13 is of a sufficient magnitude, exposes the orifice by means of which the particular duct terminates in the chamber 39 and closes off the orifice of the other duct terminating therein. According to a modified embodiment of the present invention, the orifice in the chamber 39 of each of the ducts 10 and 13 may include a calibrated flap valve which remains in the closed position in the absence of a sufficient pressure of hydraulic medium in the particular duct.

The operation of the device according to FIG. 2 proceeds as described further hereinbelow. In this FIG., the position of the lever 4 illustrated in full lines corresponds to the closed position of the valve.

In order to remotely effect the opening of the valve by means of the remote control line 10, for example, hydraulic medium under sufficient pressure is injected into this duct. The ball 12 assumes the illustrated position, closing off the duct 13 and permitting the hydraulic medium to be discharged as indicated by the arrow. The pressure of the fluid, acting upon the piston 16, pushes the flap valve 15 back, closing off the feeder duct 18, and opens the flap valve 14, thus permitting the fluid under pressure to flow in the direction of the arrow in the compartment 31a of the cylinder 31.

The piston 9, pushed back by the fluid under pressure, pushes the lever 4 by means of the cam 8, by causing the lever to rotate about its axis 32 in the direction of the arrow 0, which will result in an opening of the valve, while at the same time compressing the return spring 7. The cam 8 and the lever 4 will come to occupy the positions indicated in dashed lines in FIG. 2, corresponding to an open condition of the valve.

The hydraulic fluid pushed back by the piston 9 in the easing may escape by means of the calibrated valve 17 advantageously provided at the lower portion of the casing. In accordance with a preferred embodiment of the present invention, the water which could seep into the casing and which will be collected at 40 at the bottom thereof due to the effects of gravity, will escape ahead of the hydraulic liquid by means of the valve 17 at the time of opening of the valve. In order to minimize the water seepage, a slight excess pressure of hydraulic fluid may be produced within the casing with respect to the outer hydrostatic pressure, this excess pressure being balanced by the spring 2a connecting the diaphragm 2 with the casing 1.

As long as the pressure is maintained at a sufficient magnitude in either one or the other of the ducts 10 and 13, for example, by closing off at its upper part the duct having served to supply the cylinder 31 with fluid under pressure, in a manner such as to avoid the expansion of this fluid, the valve will remain in the open position thereof and the spring 7 will remain in a compressed state. When the pressure in the duct having served to generate the opening signal is interrupted, either by manual remote control or by an automatic control released by means of an electromagnetic valve operated by an instrument monitoring a flow parameter (pressure, rate of flow, or temperature of the production fluid), the flap valve 14 rises and closes the conduit 36 while the flap valve 15 rises and establishes communication between the compartments 31a and 31b of the cylinder 31.

The return spring 7 then expands and causes the valve to be closed by means of the cam 8 which is displaced, in this event, to the right (as illustrated in FIG. 2) from the position thereof indicated in dashed lines and the section 8a thereof comes into engagement with lever 4. The hydraulic medium filling the compartment 31a of the cylinder 31 flows through the feeder conduit 18 into the casing 1. Thus, any interruption in the control circuit automatically causes the valve to close.

The return spring 7 is preferably over-dimensioned substantially so as to compensate, on the one hand, for any loss of elasticity which may occur following a prolonged maintenance in the compressed condition while the valve is in a open condition (the duration of the production of the well, and hence, the service life of the spring, will be, for example, 20 years), and, on the other hand, a partial progressive blocking of the valve that may be caused by the formation of gum or sludge from the production fluid. In order to limit, however, the size of the spring 7, the device contemplated by the present invention comprises means appropriate for maintaining substantially constant during the entire expansion of the spring, the restoration torque which it exerts upon the key, despite the reduction of the restoring force which it produces in proportion to the expansion thereof.

For this purpose, the cam 8 is designed, in accordance with the present invention, with a profile 8a such that the product of the returning or restoring force of the spring and the lever arm of this force (distance of the axis of the spring passing through the contact point of the lever 32 on the section 8a) remains essentially constant during the entire expansion of the spring 7.

In the embodiment illustrated in FIG. 3, the opening of the valve is effected electrically by means of an electric motor 20 which is energized from the remote control location by means of the electrical energizing cable 29. When the motor 20 is set in operation, it causes rotation in the direction of the arrow 0 (corresponding to the opening of the valve) of the. toothed sector 21 associated with the key 3 of the valve. The drive of this toothed sector 21 by the motor 20, in the illustrated embodiment, is obtained by means of a system of pinions and of an irreversible couple of toothed wheel 22 and tangent screw 30.

A torque limiter 40, which may be of a conventional type, for example, a friction torque toothed is operatively interposed between the motor and the tangent screw 30. Thus, when the spherical portion 33 (F 1G. 1) engages with the stop or detent which defines the precise position corresponding to the open position of the valve, the torque limiter will permit the rotation of the motor 20 without driving the tangent screw 30 until a timed electrical delay contact secured, for of to the valve, interrupts the supply or energizing circuit of the motor 20 when the valve is in the open position.

An electromagnetic-coupling device 24 of a known type is interposed between the motor 20 and the toothed sector 21. The coupling device 24 includes an electric winding which, when it is energized by means of the conductors 26 and 27, causes the frictional coupling of two disc integral in rotation with the pinion 22 and the pinion 23, respectively. Thus, any break down in the control circuit of the coupling 24 causes uncoupling and an automatic return to the closed position of the valve. This represents an additional safety feature inherent within the apparatus contemplated by the present invention.

lt is not excluded, however, from the scope of the present invention to provide an electromagnetic-coupling device 24 of a type wherein the plates thereof are integral in the absence of an electrical excitation of the winding and are disconnected when a remotely controlled current is fed into the winding in order to open the valve.

The opening of the valve by means of the motor 20 causes compression of the spring 7 by means of the lever 4 which is supported upon the section 8a of the cam 8 by rotation about its axis. When the energization of the motor 20 is interrupted, the expansion or relaxation of the spring 7 is prevented so long as the electrical energization of the coupling device 24 prevails, since the drive system of toothed wheel 22 and tangent screw is irreversible and blocks the rotation of the toothed wheel 22 in the direction of the closed position of the valve. in order to permit the expansion of the spring 7 by causing closing of the valve, it suffices to interrupt the energization of the coupling device 24, which disconnects the pinions 22 and 23 from one another.

The closing of the valve may be carried out manually at the surface by means of a circuit breaker 28. lt is also possible to employ, jointly with this manually controlled circuit breaker 28, detecting devices of an appropriate known type which are capable of automatically causing an interruption of the electric current energizing the device 24 when the magnitude of a parameter of the production fluid, such as ithe pressure, the rate of flow or the temperature thereof in a point of the fluid exceeds some predetermined value. In order to provide two control lines of the device illustrated in the embodiment according to FlG. 2, it is sufficient to provide a second electric motor having a common shaft with the motor 20 (or a second stator winding insulated from the first one) having an electrical supply cable separate from the cable 29 and, for example, a second control winding of the coupling device 24 with an electrical-energizing circuit distinct from that of the winding 25.

The same reference numerals have been used in FIGS. 2

and 3 to designate the elements common to the two embodiments.

In the embodiment of FIG. 4, the operating member is a cam 41 wedged upon the key 3 of the valve. The cam 41 is operatively connected-with another cam 42, which is subjected to the action of a spiral return spring 43, which, upon expansion, serves to return the valve into the closed position thereof (rotation in the direction of arrow F). One extremity 44 of the spring 43 is secured to with the casing ll while the other extremity 45 thereof is associated with the cam 42.

The expansion of the spring 43 exerts upon the cam 42 a torque which is a decreasing function of the angle of rotation of the cam 42 due to the action of the spring 43. in accordance with the present invention, the cams 41 and 42 are provided with complementary sections such that the reduction of the torque supplied by the spring 43 in the course of its expansion is, at least to a large extent, compensated for by the increase of the lever arm by means of which the force of the spring is transmitted to the key. For this purpose, the respective profiles or sections of the cams 411 and 42 are designed so that when the return spring is expanded, the distance to the axis of the cam 42 of the engaging point of the two cams decrease while the distance from this point to the axis of the key 3 of the gate increases, which allows for compensating the decrease of the torque being exerted by the spring 43 on the cam 42 in proportion to or depending upon the rotation of cam 42 by virtue of the increase of the ratio of the radius at the engaging point of the cam 41 with respect to the corresponding radius of the cam 42.

The drive group of the device which affords selective remote control of the opening and closing of the valve comprises, as in the preceding embodiment, an electric motor 20 which may drive in rotation in the direction of opening of the valve an irreversible unit of toothed wheel 22 and tangent screw 39, which are operatively connected in rotation with the cam 42 by means of a coupling device 24 of the type described hereinabove. One disc of the coupling device is integral with the toothed wheel 22 and the other is connected in rotation with the cam 42 by means of a couple which in this case is reversible and consists of the tangent screw 46 and the toothed wheel 47 which is wedged upon the same axis as the cam 42 with which it is integral.

The arrow on the cam 42 corresponds to the direction of rotation thereof as the valve is opening.

While the present invention has been described hereinabove with reference to the specific details of but a few embodiments, it is to be clearly understood that the scope of the invention is not limited to these specific details, but is susceptible of numerous changes and modifications as would be apparent to one with normal skill in the pertinent technology. For example, it is possible to substitute for the spring 7 of the embodiments illustrated in F168. 2 and 3, any other elastic element such as, for example, a device enclosing an incompressible fluid and having a deformable wall (particularly a cylinder in which a piston may move). Further, it is possible to arrange the device such that the opening of the valve places the return spring in tension instead of in compression as in the illustrated embodiments. Moreover, it is feasible to utilize the apparatus contemplated by the present invention for the control of valves of the type utilizing an element which is linearly displaceable, by employing any known device, such as, for example, a rack, in order to obtain the translation of the circular motion of the control key to a rectilinear motion.

What we claim is:

I. Safety apparatus for remotely controlling the selective operation of a valve actuated by the rotation of a key means, comprising:

operating lever means secured to rotation together with said key means and having an axis of articulation,

elastic means operatively connected with said operating lever means to exert thereon a restoring force and to urge said lever means into a position corresponding to a closed position of said valve,

at least one cam means operatively connected with said elastic means, the profile of said cam means engaging at a point of said operating lever means so as to transmit said restoring force thereto, and

remotely controlled drive means adapted to move said cam means into a position corresponding to an open position of said valve and to maintain said cam means in said position, simultaneously rendering said elastic means in a stressed condition,

wherein said profile of said cam means is such that the distance between said axis of articulation and the location of the applied restoring force on said operating lever means varies substantially in inverse proportion to the magnitude of the restoring force in the course of expansion of said elastic means.

2. Apparatus according to claim 1, further comprising fluidtight casing means filled with a hydraulic medium, and wherein said drive means is hydraulically controlled.

3. Apparatus according to claim 2, wherein said hydraulic mediumis an oil emulsion in water.

4. Apparatus according to claim 2, wherein said casing means includes diaphragm means for effectively equalizing the respective pressures prevailing in the interior of said casing means and externally thereof, and calibrated relief valve means arranged in the power portion of said casing means.

5. Apparatus according to claim 2, wherein said drive means includes working cylinder means and piston means supported for reciprocal motion therewithin, said piston means being operatively connected with said cam means, at least one remotely controlled hydraulic duct operatively connected with a first chamber of said cylinder means through a distributor means by a supply conduit, said supply conduit being provided with calibrated flap valve means closing said supply conduit when the hydraulic pressure therewithin is less than a predetermined value corresponding to that at which said valve is to open, said distributor including a feeder conduit operatively connecting said supply conduit, downstream of said calibrated flap valve, with a second chamber of said cylinder means, said feeder conduit being closed by a second calibrated flap valve when the hydraulic pressure in said supply conduit exceeds said predetennined value.

6. Apparatus according to claim 5, wherein two separate, remotely controlled hydraulic ducts are in communication with said first chamber of said cylinder means, each of said ducts being in communication with a separate hydraulic medium source, and further including ball valve means effectively closing one of said two ducts wherein hydraulic pressure is below said predetermined value.

7. Apparatus according to claim 1, wherein said drive means includes at least one drive shaft capable of rotating in only one direction, at least one electric motor driving said drive shaft, torque limiting means operatively interposed between said motor and said drive shaft, electromagnetic coupling means for selectively coupling said cam means with said drive shaft, at least one electromagnetic winding for controlling the selective coupling of said cam means and said drive shaft, said winding being operatively connected with an electric-energizing circuit, and means for remotely controlling the opening of said circuit.

8. Apparatus according to claim 7, wherein said means for remotely controlling the opening of said circuit include first, manually operable circuit breaker means and second, automatically operable circuit breaker means actuated in response to a signal generated by a device sensing a flow parameter value in excess of a predetermined value.

9. Apparatus according to claim 1, further including a second cam means engaging said first cam means and wherein said elastic means includes spiral spring means acting upon said second cam means to cause said valve to assume a closed position, said drive means including a drive shaft capable of rotation in only one direction, an electric motor driving said drive shaft, electromagnetic-coupling means for selectively coupling said second cam means with said drive shaft, electricenergizing circuit means for controlling said selective coupling, and means for remotely controlling the opening of said circuit means.

10. Apparatus according to claim 9, wherein said first and second cam means have complementary profiles such that torque reduction resulting from expansion of said spiral spring means is substantially compensated for by an increase in the effective length of said operating lever means. 

1. Safety apparatus for remotely controlling the selective operation of a valve actuated by the rotation of a key means, comprising: operating lever means secured to rotation together with said key means and having an axis of articulation, elastic means operatively connected with said operating lever means to exert thereon a restoring force and to urge said lever means into a position corresponding to a closed position of said valve, at least one cam means operatively connected with said elastic means, the profile of said cam means engaging at a point of said operating lever means so as to transmit said restoring force thereto, and remotely controlled drive means adapted to move said cam means into a position corresponding to an open position of said valve and to maintain said cam means in said position, simultaneously rendering said elastic means in a stressed condition, wherein said profile of said cam means is such that the distance between said axis of articulation and the location of the applied restoring force on said operating lever means varies substantially in inverse proportion to the magnitude of the restoring force in the course of expansion of said elastic means.
 2. Apparatus according to claim 1, further comprising fluidtight casing means filled with a hydraulic medium, and wherein said drive means is hydraulically controlled.
 3. Apparatus according to claim 2, wherein said hydraulic medium is an oil emulsion in water.
 4. Apparatus according to claim 2, wherein said casing means includes diaphragm means for effectively equalizing the respective pressures prevailing in the interior of said casing means and externally thereof, and calibrated relief valve means arranged in the power portion of said casing means.
 5. Apparatus according to claim 2, wherein said drive means includes working cylinder means and piston means supported for reciprocal motion therewithin, said piston means being operatively connected with said cam means, at least one remotely controlled hydraulic duct operatively connected with a first chamber of said cylinder means through a distributor means by a supply conduit, said supply conduit being provided with calibrated flap valve means closing said supply conduit when the hydraulic pressure therewithin is less than a predetermined value corresponding to that at which said valve is to open, said distributor including a feeder conduit operatively connecting said supply conduit, downstream of said calibrated flap valve, with a second chamber of said cylinder means, said feeder conduit being closed by a second calibrated flap valve when the hydraulic pressure in said supply conduit exceeds said predetermined value.
 6. Apparatus according to claim 5, wherein two separate, remotely controlled hydraulic ducts are in communication with said first chamber of said cylinder means, each of said ducts being in communication with a separate hydraulic medium source, and further including ball valve means effectively closing one of said two ducts wherein hydraulic pressure is below said predetermined value.
 7. Apparatus accordIng to claim 1, wherein said drive means includes at least one drive shaft capable of rotating in only one direction, at least one electric motor driving said drive shaft, torque limiting means operatively interposed between said motor and said drive shaft, electromagnetic coupling means for selectively coupling said cam means with said drive shaft, at least one electromagnetic winding for controlling the selective coupling of said cam means and said drive shaft, said winding being operatively connected with an electric-energizing circuit, and means for remotely controlling the opening of said circuit.
 8. Apparatus according to claim 7, wherein said means for remotely controlling the opening of said circuit include first, manually operable circuit breaker means and second, automatically operable circuit breaker means actuated in response to a signal generated by a device sensing a flow parameter value in excess of a predetermined value.
 9. Apparatus according to claim 1, further including a second cam means engaging said first cam means and wherein said elastic means includes spiral spring means acting upon said second cam means to cause said valve to assume a closed position, said drive means including a drive shaft capable of rotation in only one direction, an electric motor driving said drive shaft, electromagnetic-coupling means for selectively coupling said second cam means with said drive shaft, electric-energizing circuit means for controlling said selective coupling, and means for remotely controlling the opening of said circuit means.
 10. Apparatus according to claim 9, wherein said first and second cam means have complementary profiles such that torque reduction resulting from expansion of said spiral spring means is substantially compensated for by an increase in the effective length of said operating lever means. 